The present invention relates to apparatus for developing and strengthening the muscles of the back; more particularly, the invention relates to a device for strengthening the erector spinae and quadratus lumbarum muscles. In order to properly strengthen the lumbar extensor muscles it has been scientifically shown that isolation of these muscles during exercise is necessary to produce a functional increase in their strength.
Isolation of the spinal erector muscles is accomplished by isolating the lumbar spine, which may be done by anchoring the pelvis so that no pelvic movement is possible. Once this is done, the objective is to rotate the torso upward in relation to the pelvis, which is restrained, causing a contraction of the spinal erector muscles. This isolation of lumbar function from pelvic function is very important in producing a productive exercise for the spinal erector muscles.
A machine has been developed for isolating, testing and exercising the muscles of the lumbar spine, by MedX Corporation of Ocala, Fla., and research conducted with this machine has established that a specific exercise for lumbar muscles will increase strengths to an enormous degree as a result of a once-a-week training program conducted for a period of 10-12 weeks. This machine operates by anchoring the patient's thigh while in a seated position on the machine, providing a restraint against rearward pelvic movement during the exercise, and a knee restraint to prevent upward knee movement during the exercise. The feet are placed in a position so as to receive a force imposed against the bottom of the feet. This force is transmitted to the knee ends of the femurs by the lower legs and will produce a resultant force in two directions; approximately 70% of the force will drive the femurs toward the rear, thus pushing the pelvic/hip sockets to the rear; while an equal force will push the knee ends of the femurs upwards, which upward movement is prevented by the knee pads. Thus, the region above the patient's upper thighs becomes a fulcrum which redirects the upward force on the knees to a downward force on the pelvic/hip sockets, and the resultant force pushes the pelvis toward the rear and downwards. The testing results from using this machine have been reported in an article entitled "Spinal Rehabilitation," Michael N. Fulton, M.D., published in 1993.
Isolation of the spinal erector muscles may also be accomplished by tilting the patient's torso forward while the patient is in a kneeling or sitting position at an angle of 30.degree. relative to the horizontal, with the forward movement of the patient's body being restrained by pads engaged against the knees. The patient's pelvis is isolated by a thigh restraint applied over the upper thigh region of the leg and a waist restraint is placed about the patient's waist to prevent the patient's pelvis from rotating during the exercise. The combination of these restraints provides isolation of the lumbar spinal movement and prevents pelvic rotation around the hip sockets, all of which causes the spinal erector muscles to become exercised when the patient bends forwardly and rearwardly about these restraints.